CA2264722A1 - Silane-treated clay production method, silane-treated clay and composition containing same - Google Patents

Abstract

An effective production method for silane-treated clays having exceptional reinforcing effects with respect to rubber, and compositions using these silane-treated clays are offered. With the silane-treated clay production method, a functional silane is predispersed or emulsified in water by means of a surfactant in order to mix the functional silane with kaolin clay and thereby uniformly surface-treat the kaolin clay with the functional silane. The surfactant should preferably be a non-ionic surfactant with an HLB value in the range of 8-18. The silane-treated clay formed by surface-treating kaolin clay by means of these functional silanes characteristically contains low residual levels of the non-ionic surfactants. The functional silanes can be either vinyl or sulfur functional silanes. The silane treated clays are useful as fillers or extenders in rubber compositions, particularly those employing silicas and/or carbon blacks.

Description

1015202530W0 98/10013CA 02264722 1999-03-01PCT/US97/15108S I LANE — TREATED CLAY PRODUCTION METHOD . S I LANE — TREATEDCLAY AND COMPOS IT ION CONTAINING SAME Field of the InventionThe present invention is directed to silane—treatedclays for use in natural or synthetic rubber systems as areinforcing filler or extender.Background ArtIn the prior art, the use of silane treated clays asfillers for polymers or elastomerics is known. Typically,treated clays employing sulfur functional silanes ‘areutilized in sulfur cured elastomeric systems requiringproperties such as high tensile strength, high modulus orthe like. Sulfurautomotive applications such as tires,cured elastomers are often found ini.e., carcass, tiretread and white side walls, belts, hoses or the like.Peroxide cured elastomeric systems are often used inand injacketing applications, such as for wire and cable,specialty goods such as gaskets. Typically, these types ofelastomeric systems seek good compression set properties.Vinyl functional silanes have been used in theseapplications.With ever increasing competition in the elastomerindustry, more and more applications are being developedwhich need high levels of reinforcement, either in termsof modulus,date,tensile strength, tear or compression set. Tosilica or carbon black fillers have been the onlytypes of fillers which could provide the desired level ofreinforcement. However, both of these filler systems arenot without their disadvantages. Carbon black generallycannot be used in applications wherein the elastomercompound needs to be pigmented (i.e., white or non—black).In addition, a very" fine particle size carbon. black isneeded to provide high levels of reinforcement and these.._._.-....q..........._.......................—-.-WWW -.~» ~— l015202530W0 98/10013CA 02264722 1999-03-01PCT/US97/151082carbon blacks can be extremely expensive. Further, in manytire related applications carbon blacks are known tocontribute to higher heat build-up properties, as comparedto clays, which can have deleterious effects on theservice life of the tire.Using a precipitated or fumed silica as a filler alsocontributes greatly to the cost of the compound sincethese silicas are often extremely expensive on a per poundMoreover, they difficult to process inbasis. areelastomeric systems. Since silica fillers have extremelyhigh surface areas, they are highly absorptive. When mixedwith a given elastomeric compound, the silicas tend toplasticizers or the like in the compounddifficult to the Thisabsorb the oils,and make it mix compound.characteristic can often lead to ‘poor’ filler‘ dispersionthereby reducing expected physical properties. The use ofhigh levels of precipitated silica in tire tread compoundsprovides excellent rolling resistance properties, but itis also known to cause the build-up of undesirable staticcharge such that they require the co-use of other semi—conductive fillers. Ideally, these replacement fillersshould have virtually no deleterious effects on rollingresistance and rubber physical properties as compared tosilica. 'However, if one were seeking to produce a non—blackelastomeric compound having a high level of reinforcement,silica and its attendant disadvantages would be the onlychoice. Carbon black cannot be used due to the need forpigmentation or color in the compound.Silicas have been combined with other silanes for usein elastomer systems. U.S. Pat. No. 5,008,305 describes areinforcing’ silica for‘ use in silicone elastomers. Thereinforcing silica is prepared by treating the dry silicawith a combination of both phenylalkoxysilane and1015202530CA 02264722 1999-03-01W0 98/10013 PCTIUS97/151083vinylalkoxysilane. This combination of surface treatmentimproves compression set and heat aging in siliconeelastomers. This differs from the _present invention inthe use of silica as a reinforcing agent and that bothphenyl and vinyl functional silanes are added to thesilica in pure form rather than as emulsions. Further,both phenyl and vinyl functional silanes are required inthe .prior' art composition as opposed to the use of asingle functional silane for surface treatment in thepresent invention. Lastly, it is required that thesesilanes be volatile in order to observe the benefits.Volatility is unimportant in the present invention.U.S. Pat. Nb. 4,714,733 describes a rubbercomposition containing" an ethylene-propylene rubber, anorganopolysiloxane having at least two alkenyl groups permolecule, a silica filler, an alkoxysilane, and athiocarbamyl-containing organosilane. This prior artcomposition exhibits improved compression set and heataging. This composition differs from the ‘presentinvention in that the prior art requires the use of athiocarbamyl-containing organosilane and the filler is asilica, not a surface treated kaolin clay.have had limitedhighperformance because of their relatively low reinforcingTheirHeretofore, silane treated claysutility in elastomeric applications requiringbenefits. ability to replace or extend highperformance fillers, such as carbon black or silica, hasbeen modest at best. Known silane treated clays for use inelastomer systems not requiring high performance includeHuberThe Nucap silane treatedthe Nucap and Nulok clays manufactured by J.M.Corporation. of Macon, Georgia.clays use a sulfur functional silane in treatment levelsup to about 0.5% by’ weight of the silane based. on dry101520253035CA 02264722 1999-03-01W0 93/10013 PCT/US97/151084clay. Exemplary of these sulfur functional silanes include"a mercapto-silane, a thiocyanato—silane or a bridgingtetrasulfane silane. The Nucap treated clays are thereforemainly targeted for use in sulfur-cured rubber systems. Incomparison, the Nulok treated clays utilize various aminofunctional silanes in treatment levels up to about 1.0% byweight and these fillers are mainly used in peroxide-curedand theircompounds. These Nucap and Nulok products,competitive counterparts, can be based on kaolin claysubstrates ranging from fine particle size waterwashedclays, to waterwashed delaminated clays of relativelycoarse particle size to various airfloat clays.wellincreasing the amount of sulfur functional silanes on theUp to the present, it was recognized thatclay did not necessarily increase the given performance ofa given elastomeric system in a proportional manner.Diminishing incremental performance benefits are providedthe silanee.g.,about 0.5% by weight and below based on cost/performanceas silane treatment levels are increased. Thus,treatments have been held to the levels noted above,considerations.Besides the inability to provide a high level ofperformance in elastomeric systems, clay or currenttreated clays have also presented a problem in regards totheir inherent higher specific gravity than that of silicaor carbon black. The specific gravity of kaolin clay is2.6 whereas the specific gravity of silica is about 2.0 to2.2. Carbon black'srubber compounds where density is critical,specific gravity is about 1.8. Ina treated claycannot be substituted for carbon black or silica on a oneto one weight basis while still meeting the densityrequirements. In other words, less clay must be used thana given phr amount of carbon black or silica to meet thedensity requirement. In addition, the reduced weightamount of clay must still be able to impart the same1015202530CA 02264722 1999-03-01WO 98110013 PCT/US97/151085filler performance characteristics as the carbon black orsilica. Conversely, if the filled rubber compounds are tobe formulated to yield equal hardness then about 1.6 partsof clay or treated clay are normally required to replaceevery 1 part of carbon black while needing to stillmaintain other physical properties like modulus, tensilestrength and tear. At a weight ratio of 1.6/1, this putstreated clays at a cost/performance disadvantage asextenders for larger particle size of soft carbon blacksunless the silane treated clays provide a very high levelof performance.of the noted above withpresently available silane treated clay products as wellIn view disadvantagesas the limitations of silica and carbon black as fillersin elastomeric systems, a need has developed to provide asilane treated clay product which can be used as a highlyeffective reinforcement for elastomeric systems.The present invention solves this need by providing amethod of making a silane treated clay and producttherefronl which can. be used. as a reinforcing filler orextender in elastomeric systems to achieve highperformance characteristics.Silanes have been used in dispensed or emulsifiedform in applications other than those employing clays.Patent JP-06285363 describes the production ofhydrophobic fine particles of an inorganic compound (morespecificallyr particles of’ T10, pigment) by' combining’ anaqueous dispersion of the inorganic compound withsurfactant and alkylsilane for the purpose of obtaining asilicone polymer coating on the surface of fine powders.While the above patent describes a hydrophobic inorganicfine particle composition and a process to produce such acomposition, the compositions of this present inventiondiffer from the above by our demonstrated examples of1015202530CA 02264722 1999-03-01W0 98/10013 PCT/US97/151086unexpectedly high gains in cured elastomer reinforcingproperties using significantly lower levels of silanetreatments which are outside the scope of this prior art.In addition, the focus of this prior art was on the useof non functionalized alkylsilanes as opposed to thefunctional silanes utilized in the present invention.The technique of using an amino functional silaneemulsion to treat an aqueous mineral slurry is describedin U.S. Pat. No. 4,525,281. The treated mineral hasimproved dewatering properties. As with the currentinvention, a mineral is treated with a silane emulsion.However, the effective silanes of this present inventionare not amino functional silanes, but rather vinyl andsulfur functional silanes which are required tochemically interact with both the kaolin clay and theelastomer. The unexpectedly high elastomer reinforcementbenefits of the current invention could not have beenpredicted from the dewatering benefit described by theprior art.A silane emulsion is described in U.S. Pat. No.4,937,104 which is useful for making building materialsurfaces hydrophobic . The emulsion consists ofalkyltrialkoxysilane in aqueous alcohol. Although thisprior art and the current invention use silane emulsionsfor surface treatment, the current invention requiresfunctional silanes to achieve the reinforcing propertiesin elastomers. Further, the observed hydrophobicitybenefit in the prior art is unrelated to the reinforcingproperties observed in the current invention.l01520253035CA 02264722 1999-03-01W0 98/10013 PCT/US97/15108Summary of the InventionAccordingly, it is a first object of the presentinvention to provide a silane treated clay product whichfortheextenderofcan be used as a reinforcing filler orelastomeric systems. The silane-treated claypresent invention is especially well suited to use as areinforcing filler for natural and synthetic rubbersbecause the available pendant functional group (a vinyl orsulfur containing group) on the silane-treated claychemically reacts with the rubber polymer backbone duringthe curing process to yield cross-linking between the clayand the polymer. As examples of Synthetic rubber, isoprenerubber (IR), nitrile butadiene rubber (NBR), ethylene-propylene rubber (ERDM), styrene ‘butadiene rubber (SBR)and Ipolybutadiene rubber‘ (BR) are examples of differentrubbers that can be reinforced with the inventive silanetreated clay.Another object of the present invention is to providesilane treated clay products that yield superior fillerreinforcement properties in rubber relative toconventional treated claysNulok(like the various Nucap andclays). The performance benefits to be providedinclude higher tensile strength, modulus and tearproperties or improved compression set, depending on. theparticular combination used with aclay/silane givennatural or synthetic rubber lpolymer. Hence, a furtherobject of the invention is to provide high. performancetreated clays having the ability to totally or partiallyreplace soft carbon. black or silica fillers in ‘variousTheperformanceelastomeric applications on a cost/performance basis.to black likeproperties in. white or non—black rubber applications isability provide carbongreatly desired. Yet another object of the invention is toprovide treated clay products of high performance for usein sulfur cured and in peroxide cured elastomer systems.101520253035W0 98/10013CA 02264722 1999-03-01PCT/US97/151088Another particularly novel aspect of this invention is the’development of a silane treated clay' filler based onpendant thiocyanate functionality that has essentiallyequal rubber reinforcement utility when using either curesystem (sulfur or peroxide).Another object of the present invention is to providea method of making a silane—treated clay product of highsilane treatment level that is useful for high performanceelastomeric systems.A further object of the invention is tokaolinpresentthematerial and either a sulfur functional silane or a vinylutilize a hydrous clay as clay startingfunctional silane in combination with the hydrous kaolinclay. The treatment level of sulfur functional silane canvary between 0.7 to 5.0% by weight of silane based on dryclay. The vinyl functional silane amount varies from 0.2to 5.0% by weight of silane based on dry clay. Preferably,the vinyl and sulfur functional silanes range in treatmentlevel between 1.0 and 2.0% by weight of dry clay.The clay starting material can be in the form of anaqueous slurry, a dry clay or a wet crude clay for silanetreatment. For slurry treatment, it is preferred that theclay be in the form of a dispersed filter cake slurry ofessentially neutral pH when treated with the silane.Preferably, the desired silane is in the form of anaqueous emulsion when added to the clay slurry to insureproper dispersion upon mixing with the clay so as to yieldgood surface treatment uniformity. For dry clays, it ispreferred that the dry clay be charged to a solids/liquidmixer followed by addition of the silane under vigorousmixing conditions. For wet crude clays having a nwisturecontent of about 20%, it is preferred that the crude clayis first pulverized. to a small aggregate size and. thenconveyed into a mixer such as a pin mixer for combiningwith the airthesilane prior to drying, milling andclassifying to a finished product. In both cases,W0 98/10013101520253035CA 02264722 1999-03-019 PCT/US97/15108silane is again preferably in the form of an aqueousemulsion when mixed with the clay (dry or wet crude form)to insure proper wetting of the clay's surface with thetreatment agentuniformity. Hence, another object of the present inventionis to provide a Inethod. that allows for higher and tnoreeffective silane treatment levels to be applied to claysfor producing a highly reinforcing treated clay product.This object has been accomplished through the developmentand use of the silane treatment agents in emulsified form.Therefore a further object of the invention is to providea method of preparing stable aqueous emulsions of sulfurfunctional silanes as well as vinyl functional silanes forsubsequent use as clay surface treatment agents. Finally,theclays in slurry form with such silane emulsions is anotherability to homogeneously treat waterwashed kaolinobject of this invention.Other objects and advantages of the present inventionwill become apparent as a description thereof proceeds.theinvention, inIn satisfaction of foregoing objects andtheembodiment, comprises a clay which is surface treated withadvantages, present its broadesteither a sulfur functional silane at a treatment level of0.7 to 5.0% by weight of the active silane based on dryclay or a vinyl functional silane having 0.2 to 5.0% byweight of active silane based on dry clay. The clay ispreferably a hydrous kaolin clay made by waterwashing orThesilane treated clays are preferred for use in elastomericair classification techniques. sulfur functionalsystems requiring high levels of tensile strength or highmodulus. The vinyl functional silane treated clays arepreferred. in elastomeric applications desiring goodcompression set. The silane treated clays can be used as atotal or partial replacement for fillers such as silica orcarbon black in elastomeric systems. The amount of silanetreated clay filler employed in a compound willthedepend oncharacteristics such as300%,desired system density,hardness, modulus at tensile strength, tear,so as to yield good surface treatmentl01520253035W0 98/10013CA 02264722 1999-03-01PCT/US97/1510810compression set or the like; however, useful fillerloadings for these silane treated clays in natural orsynthetic rubbers typically range from 10 - 150 parts byweight of silane treated clay with respect to 100 parts byweight of rubber polymer (i.e., 10 - 150 phr).Preferred Embodiments of the InventionIn one mode, the production method of silane treatedclay of the present invention is a method wherein a kaolinclay slurry" and a functional silane are mixed togetherwith. the functional silane having been predispersed oremulsified via high speed dispersion in water by means ofsurfactants, and treating the surface of the kaolin claywith the functional silane upon heat—drying the mixture.Functional silanes are silicon—containing compoundswhichhydrolytic groups which generate silanol groups which canof theand an funct ionalinclude, within a single molecule, one or moreform covalent bonds with the surface hydroxylskaolin clay kn! means of condensation,group which can form bonds with surrounding organicmatrices. The above—mentioned. hydrolytic group can. be amethoxyl group, an ethoxyl group or the like. Typically,the functional silanes of greatest utility in thisinvention will contain 2 an: 3 alkoxy type groups. Thesealkoxy groups are hydrolytically decomposed in thepresence of water, (e.g., water contained in the kaolinclay slurry’ or’ moisture adhering’ to the surface of thekaolin clay) thereby forming silanol groups and liberatingthe corresponding alcohol. The functional silanes modifythe surface of the kaolin clay by means of chemical bondswhich these silanol groups form with the surface hydroxylsof the kaolin clay. The above—mentioned functional groupcan be a vinyl group or other ethylene—type double bond, amercapto group, a thiocyanato group, a bridgingtetrasulfane group, or other sulfur functional group.Additionally, the silane may have an alkyl group such as amethyl group, an ethyl group or a propyl group.101520253035WO 98110013CA 02264722 1999-03-01PCT/US97/1510811which contain atdouble bond or a sulfur atom,Silanes least an ethylene—typesuch as mercaptosilane,thiocyanatosilane, vinylsilane, and disilyl tetrasulfaneare preferable for use in the production. method of thepresent invention.theMethacrylsilanes can also be used inbut less preferred versusAfter thea silane—present invention, arevinylsilanes because of cost consideration.silane has been mixed into the kaolin. clay,treated clay is obtained when the resulting silanol groupsreach the kaolin silicate layer to undergo a chemicalreaction with the surface hydroxyls of the kaolin clay.Then, pendant mercapto groups, thiocyanate groups, vinylgroups or tetrasulfane groups provided on the surface_ofthe silane—treated clay are able to form a bridging,and the likethe silane treated clay has ea goodcross—linking reaction with rubber whencured. Consequently,affinity towards rubber, thus having exceptional strengthwith respect to rubber and the like. Examples of silanesof this type are the mercaptosilane, thiocyanatosilane andvinylsilane types represented by the following Formula 1and the disilyl tetrasulfane type represented by thefollowing Formula 2:(RO)2R'—Si—X(wherein R represents...(l)a methyl group or an ethylgroup, R‘ represents a Inethyl group, an ethyl group, amethoxyl group or an ethoxyl group, and. X represents avinyl group, a 3—mercaptopropyl group or a 3-thiocyanatopropyl group)(RO)3—Si— (CH2)3-SSSS— (CI—I2)3—Si— (OR) 3 . . . (2)(wherein R represents a methyl group or an ethyl group).A specific example of a suitable mercaptosilane is 3-mercaptopropyl trimethoxysilane, ea specific example «of asuitable thiocyanatosilane is 3—thiocyanatopropyltriethoxysilane; specific examples of suitablevinylsilanes are vinyltrimethoxysilane andvinyltriethoxysilane, and a specific example of a disilyltetrasulfane is bis(3—triethoxysilylpropyl) tetrasulfane.1015202530CA 02264722 1999-03-01WO 98/10013 PCT/US97l15l0812The above -mentioned silanes , particularly thethiocyanato and tetrasulfane silanes , are generallydifficult to dissolve or disperse in water because oftheir organophilic nature. By emulsifying these silanes inwater by means of high speed dispersion with surfactantsand then mixing the emulsified silanes with kaolin clay,the silanes can be more intimately mixed with the clayparticles and made to uniformly coat and adhere to thesurface of the kaolin clay (the clay particles themselvesbeing inherently hydrophilic in nature). As a result, thesurface of the kaolin clay is uniformly surface—treatedafter spray-drying, so that the silane—treated clayproduct has exceptional quality and uniformity. In theabsence of using silane emulsions for the surfacetreatment of kaolin clays, the ability to apply uniformlycoated treatments at high silane treatment levels (i.e.,of aboutsilane additions 0.7% by weight of clay orgreater) becomes increasingly more difficult. In addition,greater silane losses due to the apparent volatilizationof the treatment chemical during the product drying stephave been noted when using high treatment levels of non-emulsified silane. Non-uniform treatment of the functionalsilanes results in reduced performance benefits given theadvent of clay filler areas having no surface treatmentand other areas less effectivehaving a mul ti - layercoating of treatment. It is believed that silane lossesand non-uniform coating of silane treatments onto clay,such as with the sulfur functional silanes, has beenlargely responsible for the commercially viable fillerproducts in commerce today having been previously limitedto relatively low treatment levels of < 0.7% because theof silanerubber performance gained at higher levelstreatment was not cost effective on the basis of the small1015202530W0 98/10013CA 02264722 1999-03-01PC17US97fl510813additional performance benefit obtained .relative to theincreased cost. In summary, the ability to apply uniformsilane surface treatments onto clays (per the teachings ofthis invention) has .now allowed cost effective treatedclays of high treatment level to be developed whichfunction as highly reinforcing fillers for natural orsynthetic rubber polymers.the silanesWith the present highspeed dispersed in water with the aid of surfactants andinvention, arethen mixed into kaolin clay in this state. The silanes areemulsified into water containing surfactants, which behaveas wetting agents and emulsifiers. As surfactants for usein this case, it is preferable that the surfactants haveHLB (hydrophilic/lipophilic balance) values of 8 — 18.Non—ionic surfactants are especially preferable assurfactants. Non—ionic surfactants allow silanes to beeasily dispersed in water and form ‘particularly stablesilane emulsions wherein it is .believed that thefunctional silane is :fl1 a partially hydrolyzed form. Theformation of stable silane emulsions is particularlyadvantageous because premature self-condensation of thepartially hydrolyzed functional silane into silicone—likeoligomers has been frequently noted to decrease theexpected reinforcing benefits of the silane treatment. Itshould also be noted that the pH at which the si1ane/non-ionic surfactant emulsion was prepared is very importantto resultant silane emulsion stability as the hydrolysisof alkoxy based silanes are well known to be acid or basepromoted. Additionally,the presence of residual non—ionicsurfactants in the finished silane—treated clay productaffect theNon—ionic surfactantstypesalcoholswill not processability or quality of therubber. include ether—types andwhich havetheester polyoxyethylene ortheirpolyhydricand like as hydrophilic groups.101520253035CA 02264722 1999-03-01W0 98ll00l3 PCT/US97/151081 4Examples of non-ionic surfactants are polyoxyethylenealkyl ethers, polyoxyethylene fatty acid esters,polyoxyethylene alkylphenyl ethers, polyhydric alcoholfatty acid esters, and polyoxyethylene polyhydric alcoholfatty acid esters.More suitable non-ionicspecific examples ofalkylpolyoxyethylene alkylphenyll5—EO20—EO ethoxylated nonylphenol and20—EO ethoxylated octylphenol;fattysorbitan mono—oleate and PEG—2O sorbitolmonolaurate,12 dioleate,surfactants are polyoxyethylene ethers such asethoxylated tridecyl alcohol,9—EOethoxylated nonylphenol,ethers such as ethoxylated nonylphenol,polyoxyethylene polyhydricsuch as 5-EO ethoxylatedPEG -Thesealcohol acid estersand PEG—16 hydrogenated Castor oil.18.which havenon-ionic surfactants have HLB values of 8 —Theseoxyethylene bondssurfactant compounds(—CH2CH2O-)approximately 10non-ionicas hydrophilic groups leaveppm — 5000 ppmfinished silane—treated clay. These surfactant amounts areresidues of in thesmall enough not to influence the quality of the clayfilled rubber compositions. Typically, the amount of non-ionic surfactant used to prepare a 50% active emulsion ofan organosilane is about 5% by weight of the total silanecontent. With regard to the present invention, compoundshaving oxyethylene bonds refer to non-ionic surfactantshaving oxyethylene bonds or reactants of these non-ionicsurfactants with silanes.The pure theoretical chemical composition of hydrouskaolin clay can be represented by the formulaA1203-2SiO2-2H2O ,2.60.and its specific gravity is approximatelyIt should be noted that kaolin clay is the mineraloccurring mineralsmall butkaolinite and being a naturallysubstance it contains other ingredients invarying amounts. There is no particular restriction on thetype of kaolin clay to be used in the production method ofthe present invention. However, it is preferable thatsedimentary clays such as kaolin clay from the Tertiaryclay layer in eastern Georgia, the Cretaceous clay layerW0 98/10013101520253035CA 02264722 1999-03-01PCT/US97/15108l 5in middle Georgia or a clay layer in South Carolina beThese kaolin clays result in silane—treated. clayswithused.especially good reinforcing effectsAsidewhich haverespect to rubber. from having specific physicalproperties, these sedimentary clays have excellentparticle size and shape characteristics and result inhighly workable rubber compositions.Generally, kaolin clays have a unique chemicalcomposition, unique chemical properties and uniqueparticle morphology depending upon the origin thereof. Thefine particle size waterwashed kaolin clays taken from theTertiary layer in east Georgia have a typical oxidecomposition represented by 0.4 — 1.0% by weight of Tiow ,0.8 - 1.5% by weight of Fegg, 38.4 — 39.4% by weight ofAlgg, 44.8 — 45.9% by’ weight of SiO2, 0.02 — 0.42%. byweight of Nagx 0 - 0.19% by weight of K4), and 0 — 0.03%by weight of CaO, with an ignition loss (at 1000°C) of 13.4— 14.0% by weight.When this kaolin clay is silane—treated, theresulting silane~treated clay has a median Malvernparticle size of 0.4 — 1.0 pm and a BET surface area of 19— 23 HF/g. Additionally, a Sedigraph particle size analysisshows that the silane treated clay’ has a jparticle sizedistribution such that particles having particle sizes ofgreater than 5 pm make up less than 3% by weight,particles having particle sizes of less than 2 pm make upover 90% by’ weight, particles having particle sizes ofless than 1 pm make up over 80% by weight, particleshaving particle sizes of less than 0.5 pm make up over 70%by’ weight, and particles having’ particle sizes of lessthan 0.2 pm make up less than 50% by weight of the silane-treated clay.Airfloat kaolin clays taken from the South Carolinacrudes have a typical chemical oxide compositionrepresented by 1.0 — 2.0% by weight of TiO2, 1.0 — 2.2% byweight of Fegg, 37.3 — 39.3% by weight of Algg, 44.4 —46.4% by weight of SiO2, 0 — 0.18% by weight of Nag), 0.03W0 98/10013101520253035CA 02264722 1999-03-01PCTIUS97/151081 6— 0.63% by weight of KgL and 0 — 0.22% by weight of CaO,with an ignition loss (at l000°C) of 13.4 — 14.0% byweight.When. this kaolin clay is silane—treated, theresulting silane—treated clay has a median Malvernparticle size of 1.9 — 2.9 pm and a BET surface area of 22— 26 nfi/g. Additionally, a Sedigraph particle size analysisshows that the silane—treated. clay has a particle sizedistribution such that particles having particle sizes ofgreater than 5 pm make up less than 8% by weight,particles having particle sizes of less than 2 pm make upover 80%by" weight, particles having‘ particle sizes ofless than 1 pm make up over 70% by weight, particleshaving particle sizes of less than 0.5 pm make up over 60%by weight, and particles having particle sizes of lessthan 0.2 pm make up less than 50% by weight of the silane—treated clay.Waterwashed delaminated kaolin clays taken from theCretaceous layer in middle Georgia have a typical chemicaloxide composition represented by 0.4 - 1.2% by weight ofTiO2, 0.2 — 0.7% by weight of Fegh, 36.9 - 39.9% by weightof A1203, 44.8 — 45.8% by’ weight of SiO2, 0 — 0.38% byweight of Nag3, 0.01 — 0.21% by weight of K4) and O — 0.22%by weight of CaO, with an ignition loss (at l000°C) of 13.3— 13.9% by weight.When this kaolin. clay is silane—treated, theresulting silane—treated clay has a median Malvernparticle size of 5.0 — 6.0 pm and a BET surface area of 11— 15 n3/g. Additionally, a Sedigraph particle size analysisshows that the silane~treated. clay has a particle sizedistribution such that particles having particle sizes ofgreater than 5 pm make up less than 15% by weight,particles having particle sizes of less than 2 pm make upover 60% by" weight, particles having particle sizes ofless than. 1 pm make up over 40% by weight, particleshaving particle sizes of less than 0.5 pm make up over 20%WO 98/100131O1520253035CA 02264722 1999-03-01PCT/US97/1510817by" weight, and. particles having particle sizes of lessthan 0.2 pm make up less than 5% by weight of the silane—treated clay.The Malvern particle size measurement method is alaser light scattering method, wherein the particle sizeproperties of kaolin clay are determined on dilute aqueousdispersions and the data is analyzed on the basis of Miescattering and Fraunhofer diffraction theory. The Malvernmedian particle size values reported herein were measuredusing Malvern’s Mastersizer/E particle size unit.The sedigraph particle size measurement is a particlesedimentation method. based on Stokes Law, wherein theparticle size properties of kaolin clay are determined ondilute Thecollected Micromeriticssedimentation data is5100aqueous dispersions.and analyzed by a X—raysedigraph particle size instrument.The kaolin clay feedstock can be processed in anyknown and conventional mineral processing scheme forsubsequent coupling with the silanes disclosed herein. Inone instance, the kaolin clay feed can be produced fromthe known waterwashing process to form a fine particlesize clay of essentially neutral pH. In waterwashing, thecrude clay is made into a slurry using chemicaldispersants and then fractionated or classified to removeunwanted material and to divide the clay into the desiredThe thensubjected to any number of chemical purification/grindingtheparticle size. fractionated clay slurry isto remove and increasethetechniques impurities claybrightness to desired brightness level. Aftertheredispersai at a neutral pH for subsequent product use.filtration, beneficiated clay filter cake isSince this waterwashing technique is well recognized inthe art, a further description thereof is not needed forunderstanding of the invention.Alternatively, the kaolin clay to be combined. withthe silane can be an airfloat type. Airfloat clay isobtained by crushing crude clay, drying it and airWO 98/10013101520253035CA 02264722 1999-03-01PCT/US97/15108l 8classifying it to remove unwanted materials and to achievea particular particle size.Thetreatment can also be 21 delaminated clay which combineskaolin clay starting material for silanethe processing sequences used in waterwashing with anadditional media based wet grinding step to produce claysa higher aspectThedelaminated clays is of particular interest when treatedwith a platelet—like morphology, i.e.,ratio than just waterwashed clays. use of suchclay fillers targeted. to improve rubber compression setproperties and/or various barrier properties (such as airpermeability resistance) are desired. It should beunderstood that the kaolin clay starting material forsilane treatment can be processed according to thetechniques described above or any other known techniquesin the clay industry. Likewise, although specific claycompositions are disclosed herein below, any known kaolinclays are deemed usable for the inventive silanetreatment, treatment process and elastomeric applications.When treating slurries of waterwashed kaolin clays,addition of the functional silanes is best accomplished byusing an aqueous silane emulsion. When silane treating anit is preferred to use a dry solids/liquidblender,to mix the dry clay with theairfloat clay,mixing device such as a ribbon pin mixer,Littleford blender, etc.,silane emulsion. The functional silanes are added to thedry clay solids in emulsified form under intimate mixingconditions. The silane—treated. clay’ product can then bedried to remove residual moisture and pulverized.waterwashed kaolin clay’ products have aand high brightness. Airfloatbuthave aTypically,fine particle size clayproducts have a fine particle size are a lowbrightness. Delaminated clay products coarserparticle size, higher aspect ratio and slightly lowerbrightness than non—delaminated waterwashed clay products.The silanes are high speed dispersed into water inthe presence of surfactants to form a silane emulsion. InW0 98/10012510l520253035CA 02264722 1999-03-01PCT/US97Il5l08l 9order to efficiently" and. uniformly disperse the silanesthesurfactants and water should be agitated vigorously. Ainto the water, fluid mixturecontaining silanes,silane dispersion fluid wherein silanes have been pre-dispersed in surfactant-containing waterprepared prior to mixing the silanes with the kaolin clay.The concentration of the silanes in the silane dispersionfluid should be 25 — 60% Additionally, theamount of surfactant used. should. be 0.5 — 10 parts byby weight.weight, more preferably’ 2.0 — 5.0 parts by" weight withrespect to 100 parts by weight of the silane. It ispreferable that the surfactants employed have HLB(hydrqphilic/lipophilic balance) values of 8 - 18 andvarious non-ionic surfactants are especially preferable as‘the surfactants. The above—mentioned silane dispersionfluid is pH—adjusted depending upon the type of silane,prior to mixing with the kaolin clay.If the pH of a silane dispersion fluid wherein sulfuratom—containingmercaptosilanes, thiocyanatosilanes ordisilyl tetrasulfanes are dispersed in water with asurfactant is adjusted to be alkaline, for example in thethen the sulfur functional silaneThat is, if the pH of thethen thepH range of 7.5 — 10,emulsion. can. be stabilized.silane dispersion fluid is alkaline in this way,sulfur functional silane can be prevented from being lostselfoligomers or polymers before reacting with the surfaceby means of silanol condensation into siliconehydroxyls of the kaolin clay.On the other hand, if the pH of a silane dispersionfluid. wherein. vinyl functional silanes are dispersed inwater‘ in the presence of surfactants is adjusted to beacidic, for example in the pH range of 3.0 — 5.0, or to bealkaline in the pH range of 7.5 — 10.0, then the silaneemulsion can be stabilized. If the pH of the silanedispersion fluid is adjusted in this way, then the vinylfunctional silane can be prevented from being lost bymeans of silanol self condensation before ever reactingshould be’WO 98/10013101520253035CA 02264722 1999-03-01PCT/US97/1510820with the kaolin clay. The pH of the silane dispersionfluid can be adjusted by adding alkaline or acidicsubstances such as sodium hydroxide, potassium hydroxideor acetic acid.The silane dispersion fluid is mixed with a kaolinclay powder, or more preferably, with a clay slurrywherein kaolin clay has been suspended in water. When thesilane dispersion fluid, and the kaolin clay slurry arecombined, two miscible fluids are being mixed, thus makingit especially easy to uniformly mix together the silaneand the kaolin clay. As a result, the required mixing timebecomes shorter and the silanes are distributed uniformlyon to the surface of the kaolin clay particles. The solidsconcentration of kaolin clay in the slurry is typically 40— 70% by weight but more preferably 50 — 60% by weight asdispersed clay filter cake slurries are conveniently used.In treating waterwashed kaolin clays, the addition ofa silane emulsion to clay slurry normally occurs at thedispersed clay filter cake stage. The clay slurry at thispoint in the waterwashed beneficiation process istypically 50-60% solids and has a pH value falling intothe range of 6.0 - 8Ø Addition of the silane emulsioncan be handled in one of several ways so long as it isintroduced to the dispersed clay slurry under good mixingvia a Cowles mixer or in-line mixerconditions (e.g.,injection). After mixing 'the treated clay slurry asufficient time to achieve good treatment uniformity, theproduct is then spray—dried using typical commercialdrying conditions.In the case of silane treating an airfloat clay, thisis best accomplished through the use of a drysolids/liquid mixing device (such as a ribbon blender, pinmixer, Littleford blender, etc.). The functional silanesare again best applied in emulsified form. After intimatemixing" of the clay" and silane emulsion, the product isthen dried to remove residual moisture and pulverized.WO 98/10013101520253035CA 02264722 1999-03-01PCT/US97/1510821The functionaltreatment mixture should preferably be 0.2 —the5 parts byamount of vinyl silane inweight with respect to 100 parts by weight of dry kaolinclay. If the treatment amount is less than 0.2 parts byweight, then the surface treatment effect of the silane onreinforcement is not sufficient, and an amount of greaterthan 5 parts by weight is excessive and uneconomical. Morethe silane amount varies between about 1.0 andIn thethe preferred treatmentpreferably,2.0 parts by weight for vinyl functional silanes.case of sulfur functional silanes,amounts range from 0.7 to 5.0 parts by weight, while 1.0 —2.0 parts by weight are most preferred. When vinylfunctional or sulfur functional treated clays havingsilane treatment levels of 1.0 — 2.0% by weight of dryclay are prepared with silane emulsions in accordance withthe teachings of this invention, high performance as wellas cost effective rubber compositions are obtained.After thedispersion fluid have been mixed, heat drying this mixturekaolin clay slurry and silanevia conventional spray—drying or flash—drying causes achemical reaction. between the hydrolysed silane and thesurface hydroxyls of the kaolin clay, thereby resulting ina silane surface—treated clay by means of a functionalAdditionally, thetreated clay as a dry powder. a conventionalsilane. heat drying provides silaneFor example,have an inlet airspray—dryer adjusted so as totemperature of 400 — 650%l and an outlet temperature ofabout 120°C can be used for heat—drying silane~treated clayWhile 10 ppm —surfactantsslurries. 5000 ppm of surfactants such asthethe amount is sufficiently small as to notnon—ionic normally remain in silane-treated clay,have any adverse effects on the physical properties of theclay filled rubber compositions.While the theinvention can. be applied. to many’ different uses,silane—treated clay of presentit issuited for use as a filler for synthetic resins such aspolyethylene or polypropylene, or as a reinforcing filleror extender for natural or synthetic rubbers. The silane-W0 98/10013101520253035CA 02264722 1999-03-01PCTIUS97/151082 2treated clay of the present invention is especially suitedto use as a reinforcing filler for natural and syntheticrubbers because the pendant functional group (a vinyl orsulfur containing group) on the silane—treated claychemically’ reacts with. these rubber polymers during' thecuring ‘process to ‘yield .reinforcement via cross-linkingbetween the clay and the polymer. As examples of syntheticnitrile butadiene rubber(EPDM) Iand polybutadiene rubberrubber, isoprene rubber (IR),(NBR), ethylene—propylene rubberrubber (SBR)By adding 10 —withstyrene butadiene(BR)150 parts by weight of silane—treated clay100synthetic rubber, itcan be given.respect to parts by weight of natural oris possible to obtain a compoundRubberexcellentexceptional mechanical strength.with this filleras well as making rubber productshavingcompositions loading havephysical properties,more economical. The silane—treated clay’ of the presentinvention can provide compositions of white color orenable the making of color pigmented rubber products.A silane—treated clay to be added to rubber for thepurpose of enhancing modulus, tensile strength or tearproperties should. preferably be a fine powder having aclay particle size of at least 90% less than. 2 pm asdetermined by x-ray Sedigraph, and a BET surface area of19 ~ 28 U3/g. If the particle size is small and the surfacearea is large for a silane—treated clay in this way, thenit will have good reinforcing strength with respect tothecompression set properties,rubber. However, in case of improving rubbera silane treated clay fillercomprised of a delaminated type kaolin clay derived fromCretaceous clay crudes having" a clay particle size ofabout 70% less than 2 pm as determined by x-ray Sedigraph,sometimesand a BET surface area of 11 — 15 rm/g ispreferred as the clay starting material. Such delaminatedclays are also known to provide good barrier propertiesto various rubber goods.WO 98/10013101520253035CA 02264722 1999-03-01PCTIUS97/151082 3While the above—mentioned rubber composition containsa silane—treated clay and natural or synthetic rubber asnecessary components, vulcanizing agents, cross—linkingagents, vulcanization accelerators, age resistors,antioxidants, UV absorbents, plasticizers, lubricants,flame retardants, or other fillers such as silica orcarbon black can also be added if necessary. Additionally,are no the method ofthe compositions of thethe desired. product can be obtained throughwhile there restrictions toprocessing rubber presentinvention,calendaring, extrusion molding,compression molding,injection molding or the like.ExamplesHerein below, the present invention will be explainedthealways indicate parts by weight andin detail with the use of examples. In the examples,terms "parts" and "%"O1 by weight.Examples 1-3Silane—treated, waterwashed clays wherein kaolin claywas surface—treated by means of mercaptosilane andthiocyanatosilane were produced in the following manner.Kaolin clay recovered from the Tertiary clay layer ofEastern Georgia (hereinafter referred to as Clay A) wasmade into a slurry by adding water and a chemicaldispersant. This slurry was then beneficiated to removecoarse clay and low brightness impurities, filtered andredispersed to provide a dispersed filter cake slurry(hereinafter referred to as Slurry A) having a 50% solidsthen dried andchemically analyzed, whereupon Clay A was found to containconcentration of Clay A. Slurry A was0.71% TiO2, 1.14% Fe2O3, 38.89% A1203 45.34% sioz, 0.22%Na;L 0.09% K§L and 0.01% CaO; with an ignition loss of13.68%. An example of Clay A is J.M. Huber Corporation'sPolyfil HG—90,brightness hydrous kaolin clay.a waterwashed ultrafine particle size, highCA 02264722 1999-03-01WO 98/10013 PCT/US97/1510824A dispersion fluid (hereinafter referred to asDispersion Fluid M) wherein 3—mercaptopropyltrimethoxysilane (CHJN3-Si—CJgSH (hereinafter referred to101520253035as Silane M) was emulsified in water and was prepared inthe following manner. Dispersion Fluid M was obtained byemulsifying Silane M into water by mixing Silane M into a1.0%sorbitan—monolaurateaqueous solution of PEG—20 sorbitol monolaurate (aPOE ether with 20 moles of addedethylene oxide) which is a non—ionic surfactant having anHLB value of 16.7,an alkali such as sodium hydroxide.then adjusting the pH to 8.0 by addingThe concentration ofSilane M in Dispersion Fluid M was 50%.A dispersion fluid (hereinafter referred to asDispersion Fluid T) wherein 3—thiocyanatopropyltriethoxysilane (CggO)2—Si-CJQSCN (hereinafter referred toas Silane T) was emulsified in water and was prepared inthe following manner. Dispersion Fluid T was obtained byemulsifying Silane T into water by mixing Silane T into athenThe1% aqueous solution of PEG—20 sorbitol monolaurate,the pH to 8.0 by alkali.concentration of Silane T in dispersion Fluid T was 50%.adjusting adding anTreated clay slurries were obtained by mixing SilaneDispersion Fluid T withtheDispersion Fluid M or SilaneSlurry Z; by‘ means of an agitator. In both cases,liquid Silane Dispersion Fluids M and T were able to beuniformly mixed into Slurry A in a short time. Threedifferent treated slurries were prepared by mixing eitherSilane Dispersion Fluid. M or Silane Dispersion. Fluid. Tinto Slurry A such that the amount of Silane M or Silane Twould be 0.7 -weight of active Clay A.Then,to a spray dryer having an air inlet temperature between1.3 parts with respect to 100 parts byeach of the treated clay slurries were suppliedabout 400 — 650°C for heating, whereby Silane M or Silane Twas chemically reacted with Clay A. After spray drying, asilane—treated clay product wherein 3—mercaptopropyltrimethoxysilane was chemically bonded to the surface ofClay A(hereinafter referred to as Clay AM) and silane-CA 02264722 1999-03-01W0 93/10013 PCT/US97/151082 5treated clays wherein 3—thiocyanatopropyl triethoxysilanewas chemically bonded to the surface of Clay A(hereinafter referred to as Clay AT) were obtained in fine101520thesilane—treated clay formed by mixing 1.1 parts of Silane MClay A will bethe silane—treated clay formedpowder form. Of the resulting silane—treated. clays,with respect to 100 parts of activereferred to as Example 1,by mixing 0.7 parts of Silane T with respect to 100 partsof active Clay A will be referred to as Example 2, and thesilane—treated clay formed by mixing 1.3 parts of Silane Twith respect to 100 parts of active Clay A will bereferred to as Example 3.The results of physical property measurements, suchas average particle size and particle size distribution,of Clay AM according to Example 1 are shown in Table 1.The silane—treated Clay AM according to Example 1 was awhite with a Sedigraph Average Stokesfine powderEquivalent particle size of 0.26 pm, and the concentrationof particles of less than 2 pm was found to be 96.1%. Theamount of residual non—ionic surfactant remaining in thesilane—treated Clay AM of Example 1 was 220 ppm.CA 02264722 1999-03-01W0 98/100121 PCTlUS97l1510826TABLE 1EXAMPLE 1silane—treated Clay Name silane—treated Clay AMType of Silane MsilaneAmount of 1.1 parts by weightSilaneAverage-Particle Size (Sedigraph) pm 0.26Particle Size Distribution (Sedigraph):more than 10 um % 1.00more than 5 pm * 1-30less than 2 pm % 96-1less than 1 pm * 93-8less than 0.5 pm : ::'8less than 0.2 pm '4Malvern Particle Size (median value) ‘ pm 0.71BET Surface Area m2/g 21.1Aspect Ratio 4.7Brightness (TAPPI Standard) % 91.2Oil Absorption (per 100 g of clay) g 37.5Specific Gravity 2.60101520Examples 4 — 6, Comparative Example 1These Examples investigate the performance of thesilane—treated waterwashed clays of Examples 1-3 as areinforcing filler in a rubber composition.The Clay AM of Example 1silane—treated Clays A1‘ of Examples 2 and. 3 were mixed(IR),compositions and the reinforcingsilane—treated and theinto an isoprene rubber then the processability ofthe resulting IR rubbereffects of the silane—treated Clays AM and AT with respectto IR rubber were tested by the following methods. Aanti—oxidant zinc sulfur,and 75silane—treated Clay AT orprocessing aid, an oxide,stearic acid, a vulcanizing agent, benzoic acid,parts of silane—treated Clay AM,non—surface-treated Clay A were mixed into 100 parts byweight of unvulcanized IR rubber. The mixture wasmasticated. by" means of an internal mixer and finalizedwith an open faced two roll mill to yield a test materialsuitable for measuring the processability of the rubber.The mixture compression molded andwas subsequently1015W0 98/10013CA 02264722 1999-03-01PCT/US97/151082 7vulcanized to obtain test pieces suitable for‘ measuringthe the Thecompositional makeup of the above rubber compound is shownin Table 2. Additionally,AM and silane—treated clays AT are shown in Table 3 alongwith theprocessability and physical properties.physical properties of rubber compound.the types of silane—treated Claytheir rubberTheformed from IR rubber and the silane—treated Clay AM of1 will be and thecompositions formed from IR rubber and the silane—treatedmeasurement results forcompositionExample referred to as Example 4,Clays AT of Examples 2 and 3 will respectively be referredand 6.composition formed from IR rubber and a spray—dried Clay Ato as Examples 5 Comparative Example 1 is awhich has not been surface-treated.Table 2MATERIAL IYPE AMOUNT(parts byweight)Unvulcanized IR 100.00RubberFiller 75.00Processing Aid Polyethylene Type 2.50Anti-oxidant 2.0Stearic Acid 2.0Zinc Oxide (French process) 5.0Sulfur 1.60Vulcanizing N—tert-butyl-2—benzothiazyl 1.60Agent sulfenamideVulcanizing zinc Di-n-butyl-dithiocarbamate 0.50AgentVulcanizing Diphenylguanidine 0.50AgentBenzoic Acid 1.00TOTAL 1 9 1 . 7 O101520CA 02264722 1999-03-01W0 98/10013 PCT/US97/1510828Table 3EX.4 EX.5 EX.6 COMP.EX.lFiller Name Si1ane- Silane- Silane— Clay Atreated treated treatedClay AM Clay AT Clay ATType of Silane M Silane T Silane -Silane TAmount of 1.1 0.7 1.3 -Silane(parts byweight)Rheometer (T-90%) min. 5:30 5:57 5:51 5:27Durometer (Shore A) pts. 65 65 65 61Tensile Strength ' Psi 3830 3790 3460 3350Elongation % 490 520 480 600Modulus @ 100% Elongation Psi 590 500 540 280@ 200% Elongation Psi 1270 1030 1160 390@ 300% Elongation Psi 1720 1610 1780 470Tear Die "C" Pli 337 326 348 186According to Table 3, the rubber compositions ofExamples 4 — 6 have approximately the same processabilityas that of Comparative Example 1 which uses Clay A whichhas not been surface—treated. neither oftheIn other words,Clays AM or AT thethe Additionally, thecompositions of Examples 4 - 6 which used silane—treatedsilane—treated reduceprocessability of rubber.Clays AM and AT exhibit more tensile strength,modulus at 100%, 200% and 300%,thus indicating that they‘ have a remarkable reinforcinga higherand improved tear strengtheffect with respect to rubber.Example 7A silane—treated clay (hereinafter referred to asClay AV) was produced by surface-treating Clay" A withvinyltriethoxysilane (CggO)3—Si—CH=CH2 (hereinafterreferred to as Silane V) in the following manner. A silanedispersion fluid, wherein Silane V was emulsified anddispersed in water at a concentration of 40%, was obtainedat room temperature by adding Silane V to a 1.0% aqueous101520253035CA 02264722 1999-03-01W0 98/1001329solution of PEG-12 dioleate non—ionic surfactant which hasan HLB value of 10.0 and vigorously agitating. Acetic acidwas also added to the silane dispersion fluid to adjustthe pH to 4.0 to stabilize the Silane Dispersion Fluid V.Silane-treated Clay AV(Example 7), wherein Clay A issurface—treated with vinyltriethoxysilane, was able to beproduced in the same manner as Example 1, excepting thatSilane Dispersion Fluid V was used instead of SilaneDispersion Fluid M. Silane Dispersion Fluid V and Slurry Awere able to be thoroughly mixed together in a short time.Silane-treated Clay AV of Example 7, surface—treated-with 1.1% by weight of vinyltriethoxysilane was added toNBR rubber- to test the silane-treated Clay AV with respect to NBR rubber.reinforcing effect ofTable 4 showsthe compositional makeup and the physical property testingresults for a rubber composition obtained by mixing an ageresistor, zinc oxide, zinc stearate, a plasticizer, anorganic peroxide, and 100 parts of silane—treated Clay AVor calcined clay to 100 parts of unvulcanized NBR rubber,masticating, and then cross—linking with organicperoxides.The only difference between the composition ofExample 7 and the composition of Comparative Example 2 isthe NBRrubber composition of Example 7 containing silane—treatedClay AV,Comparative Example 2 containing a standard calcined claythe type of clay filler. According to Table 4,when compared with the NBR rubber composition ofhas aboutbut it is(namely, Polyfil 80 of J.M. Huber Corporation),the same elongation as Comparative Example 2,harder, has a higher tensile strength and modulus at 100%,and has better compression smallerThat is,treated with Vinyltriethoxysilaneset per permanentdeformations. the silane—treated Clay AV surface-has a much greaterreinforcing effect with respect to NBR rubber than doesuntreated calcined clay. In this case, calcined clayrefers to a x—ray amorphous, anhydrous aluminosilicateproduct produced by heating a water-washed hydrous kaolinPCT/U S97/ 15108CA 02264722 1999-03-01W0 98/ 10013 PCT/US97/ 151083 0Clay at temperatures of 550 — 1100°C (which thermallydehydroxylates the clay mineral).Table 45EX. 7 COMP. EX.2Filler Name Silane— Calcinedtreated ClayClay AVType of Silane Silane V -Amount of Silane 1.1 —(parts by wtJUnvulcanized NBR Rubber 100 parts 100 partsQuinoline-type Aoe Resistor 2 parts 2 partsZinc Oxide » . 5 parts 5 partsZinc Stearate 1 part 1 partFiller 100 parts 100 partsDi-(2—ethylhaxyl) sebacate 10 parts 10 parts1,3-bis(tertiary butyloxyisopropyl) benzine 6 parts 6 partsHardness (Shore A, pts.) 74 69Tensile Strength (kg f/cm’) 166 61Elongation (%) 380 422Modulus @ 100% Elongation (kgf/cm’) 67 20Compression Set-% Permanent Deformation(l00°C, 22 H) 12 23Vulcanization Conditions: 160°C for 20 minutes* "parts" indicate parts by weight10Examples 8 — 11These Examples involve the preparation andcharacterization of ea silane—treated, fine particle sizeairfloat kaolin clay to investigate its performance in a15 rubber composition. 101520253035CA 02264722 1999-03-01W0 98/1001331Three different silane—treated clays were prepared,wherein kaolin clay recovered from sedimentary clay inSouth Carolina. was processed into a fine particle sizeairfloat clay and this airfloat clay (hereinafter referredto as Clay B) was then subsequently mixed with theappropriate silane dispersion fluid to effect silanetreatment after drying and pulverization. Clay B wassurface treated with(Silane M) toreferred to as Clay BM),with3—mercaptopropyl trimethoxysilaneform a silane—treated clay (hereinafterClay B was also surface treated(Silane T) to(hereinafter referred. to astreated with3—thiocyanatopropyl triethoxysilaneform a silane—treated clayClay BT)bis(3—triethoxysilylpropyl)tetrasulfaneand finally Clay B was surface(hereinafterreferred. to as Silane B) to form a silane—treated clayThesefollowing(hereinafter referred to as silane—treated Clay BB).silane-treated clays were produced in themanner.The dry airfloat Clay B was intimately mixed with thesilane which was added as an emulsion using aAfter thetreated clay is then dried to remove residual moisture anddrysolids/liquid mixing device. mixing, silanepulverized.Silane-treated Clay BM was produced by surface-treating Clay B with 3—mercaptopropyl trimethoxysilanewherein Clay B was mixed with the Silane Dispersion FluidM of Example 1. silane—treated Clay’ BI‘ was produced. bysurface~treating Clay B with 3—thiocyanatopropyltriethoxysilane wherein Clay B was mixed with the SilaneDispersion Fluid T of Example 2.The thesilane—treated Clay BB was produced infollowing manner. Silane Dispersion Fluid B was obtainedby emulsifying Silane B into water by vigorously mixing(C2H5O)3—Si— (CH2)3-(hereinafter‘ referred. to as Silanesolution of 20—EO ethoxylated(a nonylphenol—polyoxyethylene ether with 20bis(3—triethoxysilylpropyl) tetrasulfaneSSSS-(CHQ3—Si—(OCJg)31.0%B) into a aqueousnonylphenolPCT/US97l 1510810152025CA 02264722 1999-03-01W0 98/100133 2moles of added ethylene oxide), which is a non-ionicsurfactant having an HLB value of 16.7, to form a silanedispersion fluid having a 40% concentration of Silane B,then adjusting the pH to 8.5 by adding an alkali(hereinafter referred to as Dispersion Fluid B).Silane-treated Clay BB was produced by surface-treating Clay B with(Silane B)mixed with the Silane Dispersion Fluid B.bis(3-triethoxysilylpropyl)tetrasulfane wherein Clay B was intimatelyA silane—treated Clay BM obtained by mixing 1.00 partof Silane M (added as Silane Dispersion Fluid M) with 100parts of active Clay B will be referred to as Example 8, asilane—treated. Clay’ BT obtained by mixing 1.00 part ofSilane T (added. as Silane Dispersion Fluid. T) with 100parts of active Clay B will be referred to as Example 9,and silane—treated Clays BB obtained by mixing 0.70 and1.00 parts of Silane B (added as Silane Dispersion FluidB) with 100 parts of active Clay B will be referred to asExamples 10 and 11 respectively.The results of physical property measurements, suchas the average particle size of the silane—treated Clay BBaccording to Example 11 are shown in Table 5. The silane-treated Clay BB of Example 11 is a fine powder having anAverage Stokes Equivalent particle size of 0.30 pm by x-ray Sedigraph, wherein 89.3% of the clay particles haveparticle sizes of less than 2 um.PCTIUS97/15108101520CA 02264722 1999-03-01W0 93/10013 PCT/US97/1510833Table 5EXAMPLE 11silane—treated Clay Name Clay BBType of Silane BSilaneAmount of 1.0 partsSilane by weightAverage Particle Size (sedigraph) pm 0.30Particle size Distribution (sedigraph): more than 10 pmMore than 5 pm * 3~°Less than 2 pm % 4'30Less than 1 pm : :9‘3Less than 0.5 pm % 7:‘:Less than 0.2 pm % 34:8Malvern Particle Size (median value) pm 2.44BET Surface Area n?/g 25.1Aspect Ratio 9.5Specific Gravity 2.60Examples 12-15The silane—treated Clays BM, BT and BB of Examples 8-11 were added to IR rubber in the proportions shown inTable 2,rubber were examined in the same manner as with Examples4-6. BT and BB areshown in Table 6 along with their test results of rubberand their reinforcing effects with respect to IRThe various silane—treated Clays BM,processability and physical reinforcement properties.According to Table 6,12-15the rubber compositions of Exampleshave approximately the same processability ascomparative Example 3 which uses Clay B that has not beenAdditionally, theExamples 12-15 which use silane—treated Clays BM,surface—treated. compositions ofBT andbetterand 300%thus showing theyThat is, theBT and BB produced from a fine(Clay B)BB were found. to have higher tensile strengths,tear strengths and higher moduli at 100%, 200%elongation than Comparative Example 3,have exceptional rubber reinforcing effects.silane—treated Clays BM,size airfloat have excellentparticle clayreinforcing effects.., .54 . ...5101520CA 02264722 1999-03-01WO 98/10013 PCT/US97/1510834Table 6EX. 12 EX. 13 EX. l4 EX‘.l5 COMP. EX. 3Filler Name Silane— Silane- Silane— Silane- Clay Btreated treated treated treatedClay BM Clay BT Clay BB Clay BBType of Silane Silane Silane Silane -Silane M T B BAmount of 1.00 1.00 0.70 1.00 -silane(parts byweight)Reometer (T=90%) min. 5.05 5.04 4.47 5.11 4.59Durometer (Shore A) 62 62 62 69 59pts.Tensile Strength (psi) 3640 3710 3720 3790 3430Elongation %' 430 420 450 460 500Modulus @ 100% 690 760 540 580 320Elongation (psi) ~Modulus @ 200% 1280 1390 950 1033 500Elongation (psi)Modulus @ 300% 2020 2170 1590 1730 840Elongation (psi)Tear Die 355 366 311 318 209IICII Example 16A silane—treated clay (hereinafter referred to asClay CV), wherein kaolin clay recovered from theCretaceous clay layer in middle Georgia was waterwashprocessed and wet ground to form a delaminated clayproduct (hereinafter referred to as Clay C) for subsequentsurface treatment with vinyltriethoxysilane. An Example ofClay (2 is Polyfil DL made by J.M.Macon,Huber Corporation ofGeorgia.The kaolin. clay recovered. fronl the Cretaceous claylayer in middle Georgia was made into a slurry by addingwater and chemical dispersants. This slurry was waterwashprocessed and wet ground to form a delaminated clay, thenfiltered and redispersed at a neutral pH to obtain SlurryThe pH of Slurry Cwas found to be 6.8 at room temperature.C having a 55% solids concentration.Slurry C was thenspray—dried and chemically analyzed, whereupon Clay C was 101520CA 02264722 1999-03-01W0 98/10013 PCT/US97/15108‘ 35found to contain 0.87% TiO2, 0.43% Fegg, 39.41% A120,45.27% SiO2, 0.28% Nagx 0.11% K53, and 0.02% CaO; with anignition loss of 13.54%. A silane—treated clay(hereinafter referred to as Clay CV) was obtained bysurface—treating Clay (2 with vinyltriethoxysilane in thesame manner as described in Example 7, excepting thatSlurry C was used instead of Slurry A. The Average StokesEquivalent particle size, particle size distribution,specific gravity, BET surface area, aspect ratio and oilabsorption of silane—treated Clay CV are shown in Table 7.Silane—treated Clay" CV’ had an Average Stokes Equivalentparticle size by Sedigraph of 0.78 pm.Table 7Example 16silane—treated Clay Name silane—treatedClay CVType of Silane Silane VAmount of 1.1 parts bySilane weightAverage Particle Size (Sedigraph) pm 0.78Particle Size Distribution (sedigraph):more than 10 um 35 2.40more than 5 pm ’5 9-20less than 2 pm 5‘ 707less than 1 pm : less than 0.5 um % 3 ‘less than 0.2 umMalvern Particle Size (median value) pm 5.55BET Surface Area ,m’/g 33.0Aspect Ratio 13Specific Gravity 2.60A rubber composition was obtained by adding silane-treated Clay CV to NBR rubberdisclosed in Example 7,in the same manner asexcepting that silane—treated ClayThepermanent deformation by compression of a molded rubberCV was used instead of the silane—treated Clay AV.article obtained by vulcanizing this rubber composition at160°C for 20 minutes was smaller as compared with thecompression set value shown in Table 4 for silane—treated101520253035CA 02264722 1999-03-01W0 98/1001336Clay AV. These data point to the utility of delaminatedclays in improving thecompression set properties ofrubber.Examples 17-18In this experiment hereafter referred to as Example17, a Silane—treated Clay .AT having a 1.00% by weighttreatment level of Silane T was prepared by treating theSlurry A)with Silane Dispersion Fluid T under good agitation andthen with theAgitation of thisdispersed filter cake slurry of Clay A (i.e ,spray-drying the mixture in accordance‘previous teachings of Examples 2 and 3.treated slurry was conducted. over a period. of about 2hours prior to spray—drying the product.1.0%The dry product,silane—treated Clay AT of treatment, was thenanalyzed by carbon combustion analysis to quantify theamount of silane treatment present on the clay. A carbonanalysis conducted in indicated antriplicate averagesilane treatment level of 0.999% for the silane-treatedClay AT of Example 17,0.997%, 0.999% and 1.002%.with the theoretical treatment level of 1.00%based. on individual readings ofThese values agree quite wellper theproportions of Clay A and Silane T used.In a subsequent treatment experiment identified asExample 18, Slurry’ A. was again treated. with a 1.0% byweight addition of Silane T; however, thethiocyanatosilane was added neat to Slurry A under goodagitation rather than as the Silane Dispersion Fluid T.After mixing the treated slurry continuously overnight(about 18 hours), Silane T visually appeared to have fullydispersed into Slurry A whereupon the treated slurry wasspray-dried. The dry product was then analyzed by carboncombustion analysis for the amount of silane treatmentpresent. Unlike the silane—treated Clay AT of Example 17,carbon analysis now indicated an average silane treatmentlevel of only 0.838%0.900%, 0.775% and 0.839%)of 1.00%.(based on individual readings ofrather than the expected valueThese treatment level data clearly demonstratePCT/US97/15108101520253035CA 02264722 1999-03-01W0 98/1001337the importance of adding Silane T as an aqueous emulsion.In the absence of any surfactant, Silane T apparentlynever completely dispersed into Slurry A and/or nevercompletely hydrolyzed even after 18 hours of mixing suchthat some silane was lost (presumably volatilized away)the surfacethesignificant variability in the individual treatment levelduring spray—drying. Furthermore, appliedtreatment is not very uniform as reflected byvalues. In contrast, the silane—treated Clay AT of Example17 yielded excellent treatment level results after mixingthe clay and emulsified silane for only 2 hours.Examples l9—3l _This experiment investigates the performance of thea reinforcingsoftsilane—treated Clay AT of Example 17 asfillercarbon blackand more particularly as an extender forin a rubber compound. The performance ofsilane—treated Clay AT of Example 17 is also directlycompared to that of a conventional, sulfur functionalsilane treated clay (namely Nucap 290 of J.M. HuberCorporation). These treated clay fillers were evaluatedhead-to—head in a vulcanized IR rubber compound inaccordance with the composition. previously‘ described inTable 2. The this IRcompound is 75.0 phr. The relative performance propertiesclay filler loading in rubberof the silane—treated Clay AT and Nucap 290 can be seen inTables 8 and 9, respectively. In addition, these rubberperformance tables show the relative capabilities of eachtreated clay to extend a soft carbon black filler like N-660. The levels of N—660 carbon black replacement examinedranged from 10%replacement up to 55% replacement. Incarrying out these extension studies, the total fillerloading was maintained at 75.0 phr so that replacement ofthe N—660 with a treated clay was done on a weight basis.The test results of rubber processability and physicalreinforcement properties are presented in Tables 8 and 9.The results for a control compound containing just N—660(at 75.0 phr)carbon black are also presented.PCT/US97/15108CA 02264722 1999-03-01WO 98/10013 PCT/US97/1510838Table 8Experiment ID Ex. 19 Ex. 20 Ex. 21 Ex. 22‘ Ex. 23 Ex. 24Filler System Sil— N-660 5; N-660 5; N~660 & N—660 & N-660 &treated Clay AT— Clay AT— Clay AT— Clay AT— Clay AT-Clay AT— Ex. 1'7 Ex. 17 Ex. 17 Ex. 17 Ex. 17Ex. 17Carbon 0/100 85/15 75/25 65/35 55/45 45/55Black/Clay %RatioRheometer 5:49 3:47 4:09 4:20 4:15 4:37(T=90%)(min.)Durometer 65 74 74 74 73 73(Shore A)(pts.)Tensile (psi.) 3450 2780 2710 2940 2820 3010Elongation, % 440 330 350 390 380 400Modulus @ 100% 680 840 810 820 820 780(psi)Modulus @ 200% 1370 1870 1740 1690 1650 1600(psi)Modulus @ 300% 2060 2600 2450 2390 2310 2300(psi)Tear Die "C" 388 376 371 369 367 367(pli.) 101520CA 02264722 1999-03-01WO 9811001339Table 9Experiment Ex. 25 Ex. 26 Ex. 27 Ex. 28 Ex. 29 Ex. 30 Ex. 31IDFiller Nucap N-660 N-660 & N-660 & N-660 & N-660 & N-660 &System 2 9 0 CB Nucap Nucap Nucap Nucap NucapClay 290 290 290 290 290Carbon 0/100 100/0 90/10 85/15 80/20 75/25 70/30B1ack/ Clay% RatioRheometer 5:50 3:58 3:55 4:02 4:04 4:12 4:07(T=90%)(min.)Durometer 65 75 74 74 74 74 73(shore A)(pts .)Tensile 3250 2390 2800 2680 2720 2660 2870(psi. )Elongatiorfi; 460 240 340 330 350 380 390Modulus @ 570 890 810 820 780 750 750100% (psi)Modulus @ 1130 2040 1840 1800 1710 1660 1610200% (psi)Modulus @ 1700 --- 2570 2500 2430 2380 2330300% (psi)Tear Die 383 358 379 376 373 371 367NC" .)properties «of ExamplestheIn comparing the performance19 and 25, the test datareinforcement provided. by the silane—treated Clay’ AT of1.0%above show superiortreatment relative to a conventional sulfurfunctional treated clay like Nucap 290. Superior fillerreinforcement is indicated by the higher tensile strengthand moduli properties of Example 19. This superiorperformance is also reflected in the relative amounts ofN-660 carbon black that can be replaced by these treatedclays while maintaining a very high modulus value. Forinstance, when comparing the performance properties ofExamples 20-24 with those of Examples 27-31,that about 50%with the 1% silane—treated Clay AT while still providing aone will noteof the N-660 carbon black can be replacedhigh 300% modulus level of approximately 2300 psi whereasonly about 30% replacement of N-660 is realized at that PCT/U S97/ 15108l0l520253035CA 02264722 1999-03-01W0 98/19013 PCT/US97/1510840same modulus when using Nucap 290. The 1% silane-treatedClay AT also provides greater tensile and better tearproperties as compared to the N—66O carbon black control(compare Examples 19 and 26). These examples allillustrate the high performance characteristics associatedwith the silane-treated clays of this invention.Examples 32-36These Examples compare the performance of Clay AT ofExample 17, a fine particle size clay having a 1%treatment level of silane T, versus four different silicasamples as reinforcing fillers in a sulfur—cured nitrilerubber formulation. Table 10 describes the nitrile rubbercompositions of Examples 32-36 and shows their relativeperformance properties.The reinforcing properties (tensile and modulus at100% elongation) of Example 36 (Clay AT) are considerablyhigher than those of the two natural silica fillers,Examples 34 and 35, even though these comparativeevaluations were made at equal filler loadings (@ 100phr) and the latter silica product was silane treated.Clay AT and Example 32 (a precipitated silica used at aloading of 60 phr) provided virtually equivalent tensilestrengths though Clay .AT provided approximately doublethe modulus at 100% elongation. Compared to the silanetreated. precipitated silica (Example 33), Clay’ AT gavethe nitrile rubber composition a slightly higher modulusvalue and significantly better compression set though notquite as high a tensile strength. In particular, the ClayAT provided the highest modulus of all the Examples and(best)gave the lowest compression set values. Thiscomparison demonstrates that a sulfur functional silanetreated clay can be used as a substitute for a rubbersystem containing precipitated silica, treated oruntreated, with a silane, without a loss in modulus valueor significant loss in tensile strength.WO 98/10013CA 02264722 1999-03-0141Table 10Comparison of Clay AT(1% Silane T)PCT/US97/15108COPrecipitated and Natural silicas in Sulfur Cured Nitrile RubberSulfur Cured Nitrile Rubber Formulations (phr)Compound Identification EX. 32 EX. 33 EX. 34 EX. 35 EX. 36Prpt’d Prpt’d Natural Natural Clay ATsilica silica — silica silica - (1% Silanew/ Silane w/ Silane T)B BButadiene—acrylonitrile 100.00 100.00 100.00 100.00 100.00copolymerPrecipitated silica 60.00 — - - - - — - - - — - — - — — - - - — — - - — — - — - --(Ultrasil VN3 SPUPrecipitated silica with - - - - -- 60.00 - - - - — - — - - - — — - — - - - - - --Silane B (Coupsil VP31130Natural silica (Sillitin — — — — - - - - — - - - -- 100.00 - — — - — — — — — - - - — — --zasflNatural silica treated - - — - - - - - — - - — - - - - - - -- 100.00 - - - — - — --with Silane B (AktisilpF—216NClay AT (1% Silane T) - - - — — — - - - - - - - — — - — — — — — - — - - —— 100.00Dioctylsebacate 10.00 10.00 10.00 10.00 10.00Zinc oxide 5.00 5.00 5.00 5.00 5.00Polymerized 1,2—dihydro- 2.00 2.00 2.00 2.00 2.002,2,4-trimethylquinolineZinc stearate 1.00 1.00 1.00 1.00 1.00Tetramethylthiuram 2.00 .00 2.00 2.00 2.00disulfideN-Cyclohexyl-2- 1.00 1.00 1.00 1.00 1.00benzothiazylsulfenamideSulfur 0.50 0.50 0.50 0.50 0.50Totals 181.50 181.50 221.50 221.50 221.50Physical PropertiesCured Time (min.) @ 160°C 20:00 20:00 20:00 20:00 20:00Durometer (Shore A) (pts.) 83 77 65 69 69Tensile Strength (psi) 3060 3360 1390 1510 2990Elongation, % 920 382 722 583 713Modulus @ 100% Elongation 280 500 260 400 540(psi)Compression Set 22 hours@ 100°C Deflection (%) 79 19 25 15 14Compression Set 70 hours@ 100°C Deflection (%) B7 28 34 21 19Compression set 22 hours@ 125°C Deflection (%) 91 34 28 22 18Compression Set 70 hours@12S°C Deflection (%) 94 44 40 31 285 1 Degussa Corp., Ridgefield Park, NJStow,2 Struktol Co.,OH l0l520253035CA 02264722 1999-03-01W0 93/10013 PCT/US97/1510842Examples 37-40These Examples compare vinyl, thiocyanato anddiamino functional silane treated clays at a fillerloading of 100 phr in a peroxide cured nitrile rubber.The complete nitrile rubber formulation is shown in Table11. The filler theExample 37treated clay used in rubbercomposition of was prepared by surfacewith a 1% 3"Si‘to yieldtreating Clay A (a fine particle size clay)treatment level of vinyltrimethoxysilane,CH=CH2 ,Clay AV’.previously used to prepare Clay AV, Example 7,the the(hereinafter referred to as Silane V‘)Clay AV‘ was made by the same production methodexcept forsilane. silane waschange in In Example 7,vinyltriethoxysilane. The rubber composition of Example38 contains the thiocyanato—functional Clay AT of Example17.The rubber composition of Example 39 contains silanetreated Clay BD which was prepared in the followingmanner. A 23% aqueous solution of a diamino silane,specifically N—[3—(trimethoxysilyl) propyl]ethylenediamine, (hereinafter referred. to as Silane D)was intimately mixed with the dry airfloat Clay B using adry solid/liquid mixing device to yield a 1% treatment ofsilane on clay. After mixing, the silane—treated clay wasdried to remove residual moisture and pulverized. Therubber composition of Example 40 contains the silanetreated Clay CV of Example 16 (Table 7), where Clay C isa waterwashed, delaminated clay.thesilane—treated claysComparative performance data of vinyl,thiocyanato and. diamino functionalin this peroxide cured nitrile rubber are shown in Table12. The Shore A hardness was approximately equal for allthough treated Clays AV’ and ATyielded rubber compositions with higher tensile strengthsthan the Clay BD or theThe vinyl—functional Clayfour Examples silanediamino~silane treatedvinylsilane treated Clay CV.AV‘high modulus at 100% elongation and very low compressionyielded a rubber composition which had a particularly101520CA 02264722 1999-03-01W0 98/1001343set indicating that vinylsilane, Silane V’, is the bestsuited silane for enhancing the reinforcing properties offine particle size clays like Clay A in this peroxide-(which iscured nitrile rubber. Example 40 using Clay CVtreated with a similar vinylsilane) also provides highmodulus and excellent compression set properties althoughits tensile strength is reduced because of the relativelyof Clay C.silane treated Clay CV is an excellent filler choice whencoarse particle size nature Nevertheless,barrier resistance properties are needed in addition toreinforcement properties. The gas barrier properties ofdelaminated clays-are well known in the prior art. Thiscomparative data also demonstrates the vastly’ improvedmodulus values, tensile strengths and compression setproperties when using the inventive vinyl or sulfurfunctional silane treated clays of the invention versusaminosilane treated clays, i.e., Clay BD.Table 11Peroxide Cured Nitrile Rubber.Formulation (phr)Butadiene-acrylonitrile 100.00copolymerTreated Clay 100.00Dioctylsebacate 10.00Zinc oxide 5.00Polymerized 1,2— , 2.00dihydro—2,2,4-trimethylquinolineZinc stearate 1.0040% Bis(t—butylperoxy- 6.00isopropyl)benzene/CaCO3Total 224.00 PCT/US97/ 15108l0l520CA 02264722 1999-03-01W0 98/1001344Table 12Evaluation of Clay AV’, Clay AT, Clay BD and Clay CV in a Peroxide Cured Nitrile RubberPhysical PropertiesCompound Identification EX. 37 EX. 38 EX. 39 EX. 40Treated Clay used in Nitrile Clay AV’ Clay AT Clay BD Clay CVRubber (1% Silane V’) (1% Silane T) (1% Silane D) (1.1% Silane V)Cured Time (min.) @ 160°C 20:00 20:00 20:00 20:00Durometer (Shore A) (pts.) 74 74 72 74Tensile Strength (psi) 2360 2290 1910 1480Elongafion,96 380 413 345 320Modulus @ 100% Elong. (psi) 950 810 810 940‘ Compression Set 22 hours@ 100°C Deflection cm 12 18 21 16Compression Set 70 hours@ 100°C Deflection 0%) 19 26 29 23Compression Set 22 hours@ 125°C Deflection 0%,) 15 28 29 29Compression Set 70 hours@125°c Deflection cm 22 34 39 33Examples 41-44These Examples compare the rubber reinforcingproperties of some fine particle size clays (untreatedand silane treated versions) to a semi-reinforcing carbonblack jJ1 a polychloroprene formulation as described inTable 13.these different fillers,In order to best compare the performance ofthey were used in amounts thatprovided essentially constant Durometer hardness.The 43 ,of Example 17,rubber compound of Exampletreated Clay ATincorporatingsilane provided thevalues_ of all Examples while the SRFprovidedhighest moduluscarbon black containing formulation, Example 44,the highest tensile strength and. best compression set.Comparing the tensile strength and moduli of the threetreated clay containing formulations,- 43,namely Examples 41the test data indicate improved reinforcement withincreased levels of silane treatment. ThenotableSUBSTITUTE SHEET (RULE 26)PCT/US97/151081015CA 02264722 1999-03-01W0 98/1001345differences in compression set appear to be more relatedto the type of clay’ used rather than showing a highClay A (aare bothof dependence on silane treatment.and Clay Bsizedegreewaterwashed clay) (an airfloat clay)theClay A)compound ofBM)fine particle clays. Surprisingly, rubbercompound of Example 41 (containing untreated hasbetter compression set properties than theExample 42(containing silane treated. Clay despitethe lack of any surface treatment. Clay BM is amercaptosilane treated airfloat clay produced inaccordance with Example 8, except that the level ofmercaptosilane applied here was 0.5% rather than 1.0% byweight. Again, using the Clay AT as a reinforcing fillershows properties, particularly modulus values, on a parwith carbon black.PCTIUS97/151081015CA 02264722 1999-03-01WO 98/10013 PCT/US97/ 1510846Table 13Comparison of Various Clays and Carbon Black inPolychloroprenePolychloroprene Formulations (phr)EX. 41 EX. 42 EX. 43 EX. 44Filler used in Clay A Clay BM Clay AT SRFPolychloroprene (0.5% (1% Silane Carbonrubber Silane M) T) BlackPolychloroprene 100.00 100.00 100.00 100.00Clay A 1 0 o . o o — — — — - - - — - - - - - - - — — - — - - — -Clay BM (0.5% — - — — — -— 100.00 - - — — - — — - - — - - - --Silane M)Clay AT (1% Silane — — — - - — — — — - - — — -- 100.00 - — - - — --T)SRF Carbon Black - - - - - — — - - - - - — — - - — — - — — —— 60.00Stearic acid 1.00 1.00 1.00 1.00Zinc oxide 5.00 5.00 5.00 5.00Magnesium oxide 4.00 4.00 4.00 4.00Ethylenethiourea 0.50 0.50 0.50 0.50Total 210.50 210.50 210.50 170.50Physical PropertiesRheometer (T=90%) 30:36 29:18 32:00 23:00(min.) @ 160°CCured Time (min.) @ 25:00 25:00 25:00 25:00160°CDurometer (Shore A) 80 78 78 76(pts.)Tensile Strength 1980 2010 2180 3130(psi)Elongation, % 690 630 370 230Modulus @ 100% 740 870 1270 920Elong. (psi)Modulus @ 300% 950 1270 2130 ---—-Elong. (psi)Compression Set 22 26 45 29 15hours @ 100°CDeflection (%)Examples 45-48These Examples compare the rubber performanceproperties of several different silane treated clays,namely Clay AT produced at various treatment levels ofSilane T ranging from 0.2% to 1.0% and Clay BM treatedwith 0.5% of Silane Mrubber. All the silane treated clays derived from Clay A(from Example 42), in isopreneand Silane T were prepared via clay slurry treatment withfluid followed byspray—drying as previously described. The isoprene rubberthe appropriate silane dispersion10152025CA 02264722 1999-03-01W0 98I10013 PCT/US97/1510847study is the thatwhich incorporates 75formulation used in this same aspreviously’ described. in Table 2,phr of treated clay. Examples 45 - 48 are listed in TableMostall the moduli and tear values in Table 14 increase in14 in order of increasing silane treatment level.the same order as increasing silane treatment level onclay thereby making the compound of Example 48 the mosthighly reinforced composition in this isoprene study. Thesilane treated clays used in the IR compounds of Examples45 — 47 the fillerscommercially available in the marketplace. The advantagesby theimprovements in silaneare very representative ofshown Example 48 therefore demonstratereinforcement provided by thetreated clays of this invention relative to those of theprior art.Table 14Clay AT and Clay BM in Isoprene RubberPhysical PropertiesEX. 45 EX. 46 EX. 47 EX. 48Sample Description Clay AT Clay AT Clay BM Clay AT(0.2% silane T) (0.4% silane T) (0.5% silane M) (1% silane T)Rheometer (T=90%) (min.) 5:35 6:13 5:10 5:25@ 160°CMooney Viscosity (ML 1+4) 36.0 33.8 34.0 36.2@ 132°C 'Scorch @ 5 point rise 12:24 13:06 9:54 12:09(min.)Durometer (Shore A)(pts.)64646465Tensile (psi)3490331037603620Elongation, %460470460450Modulus@ 100% Elongation (psi)200% Elongation (psi)300% Elongation (psi)S8055064070010301100115013501590164017702040Tear Die "C"(pli)305319346352Tear Die "B"(pli)B13B61891930Examples 49-51These Examples once again comparepropertiessurface0.2%,silanetreatedof silane treated Clay AT,and 1.0%claysvvelretreated with different levels0.4%white sidewall tire formulation of Table 15.respectively,preparedin theviawhich hasthe reinforcingbeenof silane T atsulfur—curedAll theseclayslurrytreatment with the appropriate silane dispersion fluid of10152025CA 02264722 1999-03-01W0 98/10013 PCT/U S97/ 1510848Silane T followed by spray—drying as previouslydescribed. Rubber performance results are compiled inTable 16. Examples 49 — 51 are listed in order ofincreasing silane treatment level on clay. The rubberwhich contains Clay AT having thethe bestoverall reinforcement properties as the resulting moduli,allcompressioncompound of Example 51,highest level of silane treatment, exhibitstear, and heat build-up properties are improved.Shore Aproperties are approximately the same for all Examples.should be pointed out that thetreated clays in the compounds of Examples 49 and 50 arehardness, abrasion, and setOnce again it silanevery representative of the fillers commercially availableand used in the marketplace.byimprovementsThe performance advantagesshown Example 51 therefore demonstrate thein reinforcement provided by the silanetreated clays of this invention relative to those of thetheprovided by our silane treated Clay AT of 1%prior art. In addition, greater reinforcementtreatmentlevel is derived from providing greater cross—linkdensity to the compound which is also known to have aUVexposure testing has confirmed that the rubber compoundpositive effect on reducing UV crazing properties.of Example 51 provides the best anti—crazing properties.The UV crazing properties of white sidewall formulationsis an important customer aesthetic consideration tomanufacturers of white sidewall or raised white lettertires.CA 02264722 1999-03-01W0 98/1001349Table 15PCT/US97/ 15108White sidewall Tire Formulation (phr)Chlorinated isobutylene-isoprene 60.00Ethylene—propylene copolymer 20.00Polyisoprene 20.00Treated clay 65.00Titanium dioxide 25.00Paraffin wax 3.00Stearic acid 1.00Sodium aluminosulfosilicate 0.20Phenol—novolac resin 4.00Zinc oxide 5.00Amylphenol disulfide 1.302,2’—Dithiobis(benzothiazole) 1.00Sulfur Q;§QTotal 206.00Table 16Clay AT Evaluation in a White Sidewall Tire FormulationPhysical PropertiesEX. 49 EX. 50 EX. S1Treated Clay used in Clay AT Clay AT Clay ATwhite sidewall rubber (0.2% Silane (0.4% Silane (1% SilaneT) T) T)Rheometer (T=90%) (min.) @ 160°C 17245 13305 15:43Mooney Viscosity (ML 1+4) @ 27.3 27.9 29.0121°CScorch @ 5 point rise (min.) 8:58 8:48 7:46Durometer (Shore A) (pts.) 59 S9 60Tensile (psi) 1730 1630 1440Elongation, % 600 SS0 490Modulus @ 100% Elongation (psi) 360 370 430200% Elongation (psi) 620 690 820300% Elongation (psi) 820 930 1080Tear Die "C" (pli) 232 237 271Tear Die "B" (pli) 474 482 510Compression Set 22 hours@ 100°C Deflection (%) 45.2 43.3 42.7Abrasion (abrasive index) 139 147 139Goodrich Flexure @ 50°C(AT-°c / min_) 77 / 25 89 / 22 67 / 15% Static Deflection 28.0 29.1 27.1% Dynamic Deflection 38.4 40.0 28.9% Compression Set 17.8 20.3 6.3DMA, tan 5 @ —-30°C 0.431 0.510 0.32923°C 0.405 0.361 0.41360°C 0.223 0.205 0.208CA 02264722 1999-03-01W0 98/10013 PCT/US97/1510850Examples 52-55These Examples compare the rubber reinforcementproperties of a fine particle size clay (namely Clay A)after its surface treatment with three different organo-functional silanes (silanes D, T and V respectively) in aperoxide cured EPDM rubber formulation which is shown inTable 17. In this study, all the silane treated claysderived from silanes T or V were prepared via clay slurrytreatment with the appropriate silane dispersion fluidsfollowed by spray—drying as previously described. Silanetreated Clay AD (1% Silane D) was prepared in ananalogous fashion to Clay BD of Example 39 except thatdry Clay A was used in place of a dry airfloat clay (ClayB). Rubber performance data are compiled in Table 18. Therubber compounds of Example 54 (with Clay AT, 1% SilaneT) and Example 55 (with Clay AV, 1% Silane V) bothprovide superior performance properties as compared tothe rubber compounds of Examples 52 and 53 in virtuallyall categories including Shore A hardness, tensilestrength, moduli, tear, compression set and heat build—upproperties. The silane treated clays in the compounds ofExamples 52 and 53 are representative of treated fillerscommercially available and used in the marketplace. Thistest program thereby indicates that the type of organo-functional silane, as well as the silane treatment levelused are important for reinforcement properties in thisperoxide cured EPDM rubber. It is also very interestingto note the excellent rubber performance properties ofClay AT (1% Silane T) given that Silane T is a sulfur-functional thiocyanatosilane. Such sulfur—functionalsilanes are usually thought to be most useful inproviding reinforcement in sulfur—cured rubber systems,not peroxide cured systems. This feature obviously pointsout the unique dual performance capabilities of Clay AT.CA 02264722 1999-03-01WO 98110013 PCT/US97/1510851Table 17EPDM Rubber Formulation (phr)Ethylene—propylene-diene 100 . 00polymerTreated Clays 130.00Carbon Black N-330 5.00Naphthenic petroleum oil 50.00Zinc oxide 5.00Stearic acid 1.0040% Dicumylperoxide/CaCO3 6.80Dibenzoyl—p—quinone dioxime 3.50Total 301.30Table 18Evaluation of Treated Clays in a Peroxide Cured EPDMRubberPhysical PropertiesEX. S2 EX. 53 EX. 54 EX. 55Treated Clay in EPDM rubber Clay AD Clay AT Clay AT Clay AV(1% Silane (0.4% (1% silane (1% SilaneD) Silane T) T) V)Cured Time (mj_n,) @ 160°C 30:00 30:00 30:00 30:00Durometer (Shore A) (pts.) 53 52 55 55Tensile (psi) 670 750 1000 1000Elongation, % S20 510 440 470Modulus @l00% Elong. (psi) 230 260 320 340200% Elong. (psi) 400 470 650 660300% Elong. (psi) 520 600 850 820Tear Die "C" (pli) 103 104 139 128Compression Set 22 hours@ 100°C Deflection (5%) 46.6% 47.7% 37.8% 37.8%Compression Set 70 hours@ 100°C Deflection (95) 62.2% 61.2% 52.2% 52.7%Goodrich Flexure @ 50°C(AT-oC / min.) 43 / 18 46 / 18 33 / 11 33 / 13% Static Deflection 34.1 33.2 31.7 30.1% Dynamic Deflection 34.3 34.0 28.4 26.9% Compression Set 8.51 8.27 5.03 4.93

Claims (52)

1. A treated clay product comprising a hydrous kaolin clay surface treated with a functional silane selected from the group consisting of a sulfur functional silane in an amount between about 0.7 and 5.0% by weight based on dry clay and a vinyl functional silane in an amount between about 0.2 and 5.0% by weight based on dry clay.

2. The treated clay product of claim 1 wherein the amount of the sulfur functional silane and the amount of the vinyl functional silane each range between about 1.0 and 2.0% by weight based on dry clay.

3. The treated clay product of claim 1 wherein the functional silane is the sulfur functional silane.

4. The treated clay product of claim 3 wherein the sulfur functional silane is a silicon compound represented by a formula selected from the following:
(RO)2R'-Si-X
wherein R represents a methyl group or an ethyl group, R' represents a methyl group, an ethyl group, a methoxyl group or an ethoxyl group, and X represents a mercaptopropyl group or a thiocyanatopropyl group, and (RO)3-Si-(CH2)3-SSSS-(CH2)3-Si(OR)3 wherein R represents a methyl group or an ethyl group.

5. The treated clay product of claim 1 wherein the functional silane is the vinyl functional silane.

6. The treated clay product of claim 5 wherein the vinyl functional silane is a silicon compound represented by a formula selected from the following formulas:
(RO)2R'-Si-X

wherein R' represents a methyl group or an ethyl group, R' represents a methyl group, an ethyl group, a methoxyl group or an ethoxyl group, and X represents a vinyl group.

7. The treated clay product of claim 1 wherein the hydrous kaolin clay is one of a waterwashed kaolin clay or an airfloat kaolin clay.

8. The treated clay product of claim 7 wherein the hydrous kaolin clay is one of a waterwashed kaolin clay having a fine particle size of at least 90% less than 2 microns as determined by a x-ray Sedigraph and a waterwashed, delaminated kaolin clay.

9. The treated clay product of claim 1 wherein said functional silane-containing hydrous kaolin clay is in dry form as related to its use as a reinforcing filler for polymers.

10. The treated day product of claim 9 having a residual surfactant level on a surface of the treated clay product after said hydrous kaolin clay has been surface treated and is in said dry form

11. The treated clay product of claim 10 wherein the residual surfactant level ranges between 10 ppm and 5000 ppm based on dry clay.

12. A method of making a treated clay product comprising the steps of:
a) providing a hydrous kaolin clay;
b) surface treating said hydrous kaolin clay with an amount of a functional silane selected from the group consisting of a sulfur functional silane wherein the amount is between about 0.7 and 5.0% by weight based on dry clay and a vinyl functional silane wherein the amount is between about 0.2 and 5.0% by weight based on dry clay;
and c) heat-drying said surface treated clay as needed to yield a dry product.

13. The method of claim 10 wherein the functional silane is pre-dispersed or emulsified in water using a surfactant prior to its addition to said hydrous kaolin clay.

14. The method of claim 10 wherein the amount of the sulfur functional silane and the amount of the vinyl functional silane each range between about 1.0 and 2.0% by weight based on dry clay.

15. The method of claim 10 wherein the functional silane is the sulfur functional silane.

16. The method of claim 13 wherein the sulfur functional silane is a silicon compound represented by a formula selected from the following:
(RO)2R'-Si-X
wherein R represents a methyl group or an ethyl group, R' represents a methyl group, an ethyl group, a methoxyl group or an ethoxyl group, and X represents a mercaptopropyl group or a thiocyanatopropyl group, and (RO)3-Si-(CH2)3-SSSS-(CH2)3-Si(OR)3 wherein R represents a methyl group or an ethyl group.

17. The method of claim 10 wherein the functional silane is the vinyl functional silane.

18. The method of claim 15 wherein the vinyl functional silane is a silicon compound represented by a formula selected from the following formulas:
(RO)2R'-Si-X

wherein R represents a methyl group or an ethyl group, R' represents a methyl group, an ethyl group, a methoxyl group or an ethoxyl group, and X represents a vinyl group.

19. The method of claim 10 wherein the hydrous kaolin clay is one of a waterwashed kaolin clay or an airfloat kaolin clay.

20. The method of claim 17 wherein the hydrous kaolin clay is one of a waterwashed kaolin clay having a fine particle size of at least 90% less than 2 microns as determined by a x-ray Sedigraph and a waterwashed, delaminated kaolin clay.

21. The method of claim 11 wherein the surfactant has a HLB value of 8-18.

22. The method of claim 27 wherein the amount of surfactant employed is 0.5-10 parts by weight with respect to 100 parts by weight of the functional silane.

23. The method of claim 11 wherein the surfactant is a non-ionic surfactant.

24. The method of claim 31 wherein the amount of surfactant employed is 0.5-10 parts by weight with respect to 100 parts by weight of the functional silane.

25. The method of claim 10 wherein said hydrous kaolin clay is made in slurry form and said functional silane is pre-dispersed in water using a non-ionic surfactant and said hydrous kaolin clay slurry is well mixed with said dispersed functional silane and then heat-dried to form said surface treated hydrous kaolin clay.

26. The method of claim 13 wherein the surfactant is non-ionic, has a HLB value ranging between 8 and 18 and has a concentration of about 0.5 to 10 parts by weight of surfactant based on 100 parts by weight of the functional silane.

27. The method of claim 26 wherein the surfactant is selected from the group of ether and ester types having polyoxyethylene or polyhydric alcohols as their hycrophilic groups.

28. The method of claim 27 wherein the surfactant is selected from the group consisting of polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene alkylphenyl ethers, polyhydric alcohol fatty acid esters, and polyoxyethylene polyhydric alcohol fatty acid esters.

29. The method of claim 28 wherein the surfactant is one of PEG-20 sorbitolmonolaurate and 20-EO ethosylated nonylphenol.

30. A hydrous kaolin clay slurry mixture comprising:
a) a hydrous kaolin clay slurry having an amount of hydrous kaolin clay ranging between 40 and 70% by weight of the slurry;
b) a functional silane emulsion comprising:
i) a functional silane-containing dispersion wherein the functional silane is selected from the group of a sulfur functional silane in an amount between about 0.7 and 5.0% by weight based on a dry amount fo the clay form and a vinyl functional silane in an amount between about 0.2 and 5.0% by weight based on a dry amount of the clay wherein a concentration of the functional silane in the dispersion ranges between 25 and 60% by weight; and ii) a surfactant in an amount ranging between 0.5 and 10 parts by weight based on 100 parts by weight of the amount of the functional silane.

31. The slurry of claim 30 wherein the functional silane is the sulfur functional silane.

32 The slurry of claim 31 wherein the sulfur functional silane is a silicon compound represented by a formula selected from the following:
(RO) 2R' -Si-X
wherein R represents a methyl group or an ethyl group, R' represents a methyl group, an ethyl group, a methoxyl group or an ethoxyl group, and X represents a mercaptopropyl group or a thiocyanatopropyl group, and (RO)3 -Si - (CH2)3 -SSSS- (CH2)3 -Si (OR)3 wherein R represents a methyl group or an ethyl group.

33. The slurry of claim 30 wherein the functional silane is the vinyl functional silane.

34. The slurry of claim 33 wherein the vinyl functional silane is a silicon compound represented by a formula selected from the following formulas:
(RO) 2R' - Si - X
wherein R represents a methyl group or an ethyl group, R' represents a methyl group, an ethyl group, a methoxyl group or an ethoxyl group, and X represents a vinyl group.

35. Th slurry of claim 30 wherein the surfactant is 0.5 - 10 parts by weight with respect to 100 parts by weight of the functional silane.

36. The slurry of claim 35 wherein said hydrous kaolin clay is made in slurry form and said functional silane is pre-dispersed in water using a non-ionic surfactant and said hydrous kaolin clay slurry is well mixed with said dispersed functional silane and then heat-dried to form said surface treated hydrous kaolin clay.

37. The slurry of claim 36 wherein the surfactant is non-ionic, has a HLB value ranging between 8 and 18 and has a concentration of about 0.5 to 10 parts by weight of surfactant based on 100 parts by weight of the functional silane.

38. The slurry of claim 37 wherein the surfactant is selected from the group of ether and ester types having polyoxyethylene or polyhydric alcohols as their hycrophilic groups.

39. A rubber composition comprising a rubber and a filler comprising the surface treated hydrous kaolin clay of claim 1.

40. The rubber composition of claim 20 wherein said filler is used in an amount of about 10 to 150 parts by weight of said filler for every 100 parts by weight of said rubber.

41. The rubber composition of claim 20 wherein said rubber is one of a natural or a synthetic rubber.

42. A treated clay product comprising a waterwashed kaolin clay surface treated with a sulfur functional silane comprising one of bis (3 - triethoxysilypropyl) tetrasulfane, a mercaptosilane and a thiocyanatosilane wherein an amount of said sulfur functional silane ranges between 1.0 and 2.0% by weight based on dry clay.

43. A rubber composition comprising a rubber and a filler comprising the surface treated kaolin clay of claim 23 where 10-150 parts by weight of treated clay are used for every 100 parts of rubber.

44. A treated clay product comprising a waterwashed kaolin clay surface treated with a vinyl functional silane comprising one of a vinyltrimethoxysilane and a vinyltriethoxysilane, wherein an amount of said vinyl functional silane ranges between 1.0 and 2.0% by weight of dry clay.

45. A rubber composition comprising a rubber and a filler comprising the surface treated kaolin clay of claim 25 where 10-150 parts by weight of treated clay are used for every 100 parts of rubber.

46. The rubber composition of claim 24 wherein the parts by weight of treated clay are selected so that the rubber composition has improved modulus, tensile and/or tear properties as compared to analogous rubber compositions employing an untreated kaolin clay or a conventional silane treated kaolin clay of low treatment level.

47. A rubber composition of claim 26 wherein the parts by weight of treated clay are selected so that the rubber composition has improved compression set properties as compared to analogous rubber compositions employing an untreated kaolin clay or a conventional silane treated kaolin clay of low treatment level.

48. The rubber composition of claim 43 wherein the rubber is a peroxide cured system.

49. The rubber composition of claim 48 wherein the sulfur functional silane is the thiocyanatosilane.

50. The rubber composition of claim 45 wherein the rubber is a peroxide cured system.

51. A tire having the rubber composition of claim .
39.

52. A tire having a portion of a tire sidewall formulated with a filler-containing white rubber composition the filler comprising the surface treated hydrous kaolin clay of claim 1.